/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraCommon.h
Builds a unique name from a candidate name and a set of existing names. The candidate name will be made unique if necessary by adding a 3 digit index to the end.
namespace FNiagaraUtilities { [FName](API\Runtime\Core\UObject\FName) FNiagaraUtilities::GetUniqueName ( [FName](API\Runtime\Core\UObject\FName) CandidateName, const [TSet](API\Runtime\Core\Containers\TSet)< [FName](API\Runtime\Core\UObject\FName) > & ExistingNames ) }